Microsoft announced on Monday that it would offer a £155,000 ($250,000) reward for information that leads to the arrest of the creators and operators of the Rustock botnet spam operation.

The creators of Rustock botnet, the mother of all spam bots, is based in Russia. It was reported to sent out around 30 billion spam emails per day, mostly for Viagra. They are also resposible for cyber crimes, counterfeit items and pirated software. With the help of Microsoft, the operation was shut down in March.

“Last month, I shared with you that the Rustock botnet has remained inactive since Microsoft and its partners took it offline on March 16th,” wrote Richard Boscovich, senior attorney at Microsoft’s Digital Crimes Unit. “Today, we take our pursuit a step further. After publishing notices in two Russian newspapers last month to notify the Rustock operators of the civil lawsuit, we decided to augment our civil discovery efforts to identify those responsible for controlling the notorious Rustock botnet by issuing a monetary reward in the amount of $250,000 for new information that results in the identification, arrest and criminal conviction of such individual(s).”

Rustock botnet’s size was already cut in half, still leaving thousands of systems under the spammer’s control. Microsoft is now looking to bring down the entire operation by turning to the legal system.

It’s a good thing that Microsoft is leading the charge in taking away spammers because over the years, the internet has been a dangerous place for people who don’t have enough security in their systems.